Reamer



INVENTOR C/aude 6. White ATTORNEY?? United States Patent O 3,454,118REAMER Claude C. White, 3912 Cahaba Road, Birmingham, Ala. 35243 FiledJune 28, 1967, Ser. No. 649,683

Int. Cl. E21b 9/26 U.S. Cl. 175-289 i 1 Claim ABSTRACT oFrrms-DISCLOSURE A mine roof reamer includingl'a rotatable shaft, a rammember within the shaft, the'shaft being movable longitudinally withrespect to the ram member, a wedge carried by a terminal of the rammember, blade elements having cutting members xed to a terminal of therotatable shaft and having the upper ends thereof in sliding engagementwith the wedge, the blade elements being urged progressively outwardlyby the wedge into reaming engagement with the roof inwardly thereof forforming a conical opening to receive an expansion shell carried by amine roof bolt.

This invention relates to a reamer particularly adapted for formingconical openings in mine roofs for the reception of expansion shellscarried by mine roof bolts.

Background and b jects Attempts have been made over the years to developa reamer capable of forming a conical opening in a mine roofcomplementing the shape of a roof bolt expansion shell. Up to thepresent time, these attempts have been unsuccessful due to the inabilityof the cutting members of the reamer to withstand the forces exertedthereon without permanent distortion thereof during the reamingoperation.

It is an object of this invention to provide a reamer for ,forming aconical opening in a mine roof adapted to receive an expansion shellengaged with a roof bolt, the reamer including blade elements capable ofwithstanding the distorting forces exerted thereon upon rotation andreaming engagement with the mine roof.

Another object is to provide a reamer of the character described whereinthe blade elements are constructed of a material having a high yieldpoint to effect restoration of the blade elements to their initialposition upon completion of the reaming operation.

A further object is to provide a reamer having blade elements equippedwith cutting members detachably en'- gaged with the blade elements tofacilitate ready replacement thereof as required.

Other objects of the invention will be manifest from the followingdescription of the presently preferred form of the invention taken inconnection with the appended drawing, wherein:

FIGURE 1 is an elevational view of the ramer of the present invention,portions thereof being shown in section to illustrate details ofconstruction;

FIGURE 2 is a fragmentary elevational view of the reamer of the presentinvention from the position indicated by the line 2-2 of FIGURE l,looking in the direction of the arrows, a portion thereof being shown insection;

FIGURE 3 is a longitudinal sectional view of the reamer of the presentinvention illustrating its use and showing the blade elements thereof infully extended position;

FIGURE 4 is a sectional View taken along the line 4-4 of FIGURE 1,looking in the direction of the arrows; and

FIGURE 5 is a sectional view taken along the line 5 5 of FIGURE 1,looking in the direction of the arrows.

Fice

Referring now in greater detail to the drawing, the reamer of thepresent invention includes a tubular shaft 10, the lower end of which isconnected to a conventional drill (not shown) for rotating the reamer ina well-known manner. The upper terminal of tubular shaft 10 is reducedand externally threaded as indicated at 12. A bifurcated membergenerally designated 14 is threadedly engaged with threaded portion I12of tubular shaft 10.

Bifurcated member 14 includes a lower cylindrical section 16 which isthreadedly connected to portion 12 of tubular shaft 10.

Cylindrical section 16 issues into upwardly extending, substantiallyflat blades 18 which are in opposed relationship and are provided at theupper end with forked portions 20 forming a bit pocket or recess 22.

Each pocket 22 is adapted for the reception of a cutting bit whichincludes a shank 26 which complements pocket 22, the shank issuing intoa body portion 28, the inner surface of which is angular as indicated at30. The outer surface of the bit body portion is provided with a lateralcutting edge 32 and an upwardly directed cutting edge 34. A Setscrew 36extends through one element of fork portion 20 into retaining engagementwith shank 26 of cutting bit 24 to normally hold the same in position.Setscrew 36 also facilitates removal and replacement of cutting bit 24when necessary.

It is a salient feature of the present invention to provide a bifurcatedmember 14 which is made of a material having a very high yield point inthe order of 250,000 pounds per square inch. Maraging steel has beenfound to give optimum results. Additionally, blades 18 are ofsubstantial length and the intermediate portions thereof are ofapproximately 3716 (three-sixteenths) of an inch thick in order toprovide the flexibility necessary to permit outward movement of cuttingbits 24 into reaming engagement with the mine roof.

In accordance with the objects of the present invention, a ram rod 38 ispositioned within bifurcated member -14 and of substantially the samelength as that member. The lower terminal of ram rod 38 is threaded orsecured in any other suitable manner to a bearing block 40. Spaced arms42 extend downwardly from block 40 and are xedly connected to a springabutment 44. A convolute spring 46 of substantially the same diameter asthe internal diameter of tubular shaft 10` extends through a substantialportion of that member and rests on a stationary block 48 which is xedlypositioned with `re spect to tubular shaft 10 by a Setscrew 50.

The upper terminal of ram rod 38 is threaded at 52 for engagement with awedge member designated 54. Wedge member 54 includes a generallycylindrical body portion 56, the lower end of which is reduced at 58 forthreaded engagement with portion `52 of ram rod 38. Opposed portions ofcylindrical member S6 are longitudinally tapered at 60` to provide anupwardly and outwardly extending wedge. Tapering surfaces 60 are adaptedto be engaged by inner faces 30 of cutting bits 24. By virtue of thisstructure, upon relative movement of bifurcated member 14 with respectto cylindrical member 54, cutting bits 24 are progressively urgedoutwardly.

The present reamer further includes a cap 62 engaged with the upperterminal of cylindrical member 54, a thrust bearing 64 being interposedbetween the cap and member.

Operation In use of the reamer of the present invention, the mine roofwhich is designated 66 in FIGURE 3 is drilled in conventional fashion toa predetermined depth, forming a mine proof bolt hole or opening 68which is of uniform diameter throughout its length. The reamer of thepresent invention is inserted into opening 68 until cap 62 abuts theupper limit thereof. The lower end of shaft 10 is engaged with a drivingmember (not shown) to rotate the same together with bifurcated member14. Simultaneously, pressure is exerted upwardly on the reamer to elfectcompression of spring 46 with result in upward movement of shaft 10 andbifurcated member 14 with respect to ram rod 38 and member 54. Theengagement of inner faces 30 of cutting bits 24 with tapering surfaces60 results in a flaring outwardly of the cutting bits into reamingengagement with that part of the mine roof adjacent opening `68.

As cutting bits 24 are rotated and are urged upwardly along taperingsurfaces 60, a conical recess 70 is formed in the mine roof at a pointinwardly of the lower extremity of opening 68. Conical recess 70complements the shape of an expansion shell of the type disclosed in mypreviously granted Patent No. 3,104,582. After the reaming operation iscompleted, upon release of the upward pressure on shaft 10, spring 46acts to move cutting bits 24 downwardly along tapering surfaces 60 tothe inoperative position shown in FIGURE 1.

During the reaming cycle, bifurcated member 14 is subjected to stressestending to ex blade elements 18 outwardly, and also to exert torsionalforces thereon caused by the rotation of these elements. Temporarydistortion thereof results but, due to the high yield point from whichmember 14 is constructed, these elements revert to their initial shapewhen the reaming is completed. Maraging steel has been found to giveoptimum results under actual working conditions. With the apparatus ofthe present invention also, the use of guides, tracks or other means forlimiting distortion of the blade elements is obviated.

I claim:

1. A reamer for mine roofs including:

(a) a tubular shaft,

(b) a bifurcated member connected to a terminal of said shaft,

(c) said bifurcated member including a lower cylindrical section,

(d) opposed, substantially flat blades extending upwardly from saidcylindrical section,

(e) said flat blades being made of material having the characteristicsof maraging steel,

(f) the upper terminals of the flat blades issuing into forked portionsforming recesses,

(g) cutting bits removably mounted in the recesses,

(h) a ram rod extending through said tubular shaft and bifurcatedmember,

(i) a wedge member engaged with the upper terminal of said ram rod,

(j) said wedge member having opposed tapering surfaces with which saidcutting bits are slidably engaged, and

(k) spring means within said tubular shaft and in engagemeut with thelower terminal of said ram rod to normally maintain the cutting bits ininoperative position,

(l) the cutting bits being urged progressively upwardly and outwardlyupon movement along the tapering surfaces of said wedge member whenupward pressure is exerted on said tubular shaft against the force ofsaid spring means.

References Cited UNITED STATES PATENTS 2,638,327 5/1953 Baldwin l75-288X2,692,758 10/1954 Curry et al. 175-289 35 ERNEST R. PURSER, PrimaryExaminer.

